
#div2 {
    position: absolute; /*设置为绝对定位*/
    z-index: 999;
    margin-top: -60px;
}

#tab1{
    width: 90%;
    border: dashed 1px #b1b1b1;
    height: 50px;
}
#tab1 td{
    width: 30%;
    font-size: 1vw;
}